The Neurohumoral Core will provide for all of the four projects assessment of neurohumoral function in both experimental models of cardiovascular disease and in human heart failure. Specific neurohormones to be assessed in Core C include ANP, BNP (both canine and human), CNP, aldosterone (ALDO), angiotensin II (ANG II), cyclic GMP (cGMP), cardiotropin-1 (CT-1), endothelin-1 (ET-1), plasma renin activity (PRA), and procollagen Ill (PIIINP).